Wellington journalist Phil Cottrell's killer enjoyed violence and used it casually or to get what he wanted, a judge said in sentencing him to 12 years and 10 months' jail for manslaughter.

Nicho Allan Waipuka, 20, has to serve at least eight and a half years before he can be considered for parole.

Waipuka had admitted punching Cottrell once but in the High Court at Wellington today Justice Forrie Miller accepted medical opinions that Cottrell was stomped and kicked as well.

The judge said he considered sentencing Waipuka to life imprisonment.

Waipuka showed no remorse at the time Cottrell died or now, the judge said.

Cottrell, a bulletin editor for Radio New Zealand, died from head injuries on December 11, 2011, the day after he was attacked while walking home from a work night shift.

He left work at about 5.30am in daylight for a walk of a few minutes to his flat in Victoria St, central Wellington, but Waipuka hit him, and took his wallet which contained $80.

Cottrell, 43, had a bone condition, osteogenesis imperfecta, which might have affected the way his bones broke. His skull was shattered, and he had a broken arm and fractures in several neck bones.

Waipuka and a youth who was with him, Manuel Renera Robinson, who was then 17, were charged with murder.

Robinson denied being involved in the attack and a jury last December acquitted him outright. Waipuka was acquitted of murder but found guilty of manslaughter.

Cottrell was widely travelled and had the goal of visiting at least 100 countries by the time he reached 50. At his death he had visited 73. Friends and family have continued his quest, visiting the countries he had intended to see, taking photographs and posting them on a Facebook page.